Energy loss, hadronization, and hadronic interactions of heavy flavors in relativistic heavy-ion collisions

We construct a theoretical framework to describe the evolution of heavy flavors produced in relativistic heavy-ion collisions. The in-medium energy loss of heavy quarks is described using our modified Langevin equation that incorporates both quasielastic scatterings and the medium-induced gluon radiation. The space-time profiles of the fireball are described by a (2+1)-dimensional hydrodynamics simulation. A hybrid model of fragmentation and coalescence is utilized for heavy quark hadronization, after which the produced heavy mesons together with the soft hadrons produced from the bulk quark-gluon plasma (QGP) are fed into the hadron cascade ultrarelativistic quantum molecular dynamics (UrQMD) model to simulate the subsequent hadronic interactions. We find that the medium-induced gluon radiation contributes significantly to heavy quark energy loss at high $p_{\mathrm{T}}$; heavy-light quark coalescence enhances heavy meson production at intermediate $p_{\mathrm{T}}$; and scatterings inside the hadron gas further suppress the $D$ meson $R_{\mathrm{AA}}$ at large $p_{\mathrm{T}}$ and enhance its $v_2$. Our calculations provide good descriptions of heavy meson suppression and elliptic flow observed at both the Large Hadron Collider and the Relativistic Heavy-Ion Collider.

Figure 1

The initial heavy flavor spectra from the leading-order pQCD calculation with and without the nuclear shadowing effect (EPS09), (a) for the LHC and (b) for the RHIC experiments.

Figure 2

Comparison of energy loss between different mechanisms: (a) for charm quark and (b) for bottom quark.

Figure 3

The momentum dependence of the coalescence probabilities at different flow velocities: (a) for charm quark and (b) for bottom quark.

Figure 4

Comparison between the contributions from different hadronization mechanisms to the (a) $D$ and (b) $B$ meson spectra (normalized to one heavy quark).

Figure 5

The $D$ meson (a) $R_{\mathrm{AA}}$ and (b) $v_2$ in 2.76 TeV Pb-Pb collisions [18, 19], compared between different hadronization mechanisms, and with and without the nuclear shadowing effect.

Figure 6

The $D$ meson (a) $R_{\mathrm{AA}}$ and (b) $v_2$ in 200 GeV Au-Au collisions [16, 17], compared between different hadronization mechanisms, and with and without the nuclear shadowing effect.

Figure 7

Heavy meson suppression in central Pb-Pb collisions, compared between different energy loss mechanisms and $D$ and $B$ mesons.

Figure 8

Comparison of suppression between $D,B$ mesons and nonprompt $J/\psi$ in 2.76 TeV Pb-Pb collisions [68].

Figure 9

Effects of hadronic interactions on the $D$ meson (a) $R_{\mathrm{AA}}$ and (b) $v_2$ in 2.76 TeV Pb-Pb collisions.

Figure 10

Effects of hadronic interactions on the $D$ meson (a) $R_{\mathrm{AA}}$ and (b) $v_2$ in 200 GeV Au-Au collisions.

Figure 11

The $D$ meson suppression in different centralities at the RHIC experiment.

Figure 12

The participant number dependence of the $D$ meson $R_{\mathrm{AA}}$ at the RHIC.